The present invention relates to a method for controlling a dethrottled internal combustion engine. The invention also relates to a device for controlling a dethrottled internal combustion engine. In addition, the invention relates to a dethrottled internal combustion engine equipped with such a control device.
DE 103 44 759 A1 discloses a method for controlling an internal combustion engine. The internal combustion engine controlled by the known method comprises a joint fresh gas line that supplies fresh gas to a plurality of fresh gas pipes which in turn each carry fresh gas to a cylinder. The internal combustion engine also comprises at least one intake valve per cylinder and also one pulse charging valve per fresh gas pipe for opening and closing the respective fresh gas pipe. Furthermore, a fuel injector for metered addition of fuel is provided for each cylinder. The internal combustion engine is throttled and accordingly has a throttle device, in particular a throttle valve, in the fresh gas line for load-dependent throttling of the fresh gas supplied to the individual cylinders. With the known control method, the chronological position of the injection time of the fuel is adjusted for each cylinder as a function of a point in time of a change in the switch position of the respective pulse charging valve. By coordinating the fuel injection with the pulse charging, the mixture formation process and thus the internal combustion process can be improved with respect to reducing emissions. In pulse charging by means of pulse charging valves, hydrodynamic effects are utilized to improve the fresh gas charge to the individual cylinders.
A dethrottled internal combustion engine is known from Pischinger, Variable Valve Control II, Expert Publishers, pages 244 to 260; this design is characterized by the lack of a load-dependent throttle mechanism in the joint fresh gas line. To nevertheless be able to implement a fresh gas charging of the individual cylinders as a function of the prevailing load state of the internal combustion engine with the known dethrottled internal combustion engine, the opening and closing times of the intake valves are adapted accordingly in the case of the known internal combustion engine. To do so, the known internal combustion engine works with an electromagnetic valve control for the intake valves which makes it possible to arbitrarily open and close the intake valves. Such electromagnetic valve controls are much more expensive, however, than traditional valve drives controlled by camshafts. A throttle-free or dethrottled fresh gas supply to the internal combustion engine also leads to a reduced gas exchange work and to an improved quality of the combustion process, which in turn results in reduced emissions and fuel consumption values.